January 2014 was the worst month for flight disruptions in recent history. An airline cost tracking group estimates that severe weather flight delays last month cost Americans $2.5 billion in lost business and productivity.

The cloud-based data and software company, masFlight, says airlines alone - facing the costs of rerouting flight crews, paying overtime wages and de-icing runways and aircraft - lost between $75 million and $150 million. Regional airlines accounted for 67 percent of the month's cancellations, while U.S. airlines also faced heavy impact, canceling 49,000 flights in January and delaying another 300,000.

With severe weather flight disruptions adding about 18 hours to passenger travel, many passengers lost days of work and missed income, while carrying additional expenses such as hotel rooms and meals.

MasFlight attributed the heavy impact on airlines operations in bad weather to regulatory changes such as the Department of Transportation's (DOT) tarmac delay rule, imposing $27,500 fines on carriers holding passengers on board on the ground for more than three hours, and FAR 117, which restricts the amount of time pilots can be available to fly.

Costs just might continue to pile up this month, too. The winter weather forecasts are calling for more of the same in February.